There are transport devices that, on a production line, transport a workpiece and cause a machine tool at a transport destination to apply predetermined processing to the workpiece. JP 201-93032A discloses a pallet transport device that transports a plurality of pallets, which allow workpieces to be placed thereon, so as to circulate the pallets toward a machine tool on a track shaped path composed of two linear portions and two curved lines that connect between the linear portions.
This transport device includes first and second pallet rails that extend in parallel to each other, first and second pallet feeding means for transporting the pallets along the first and second pallet rails, and pallet moving means for moving the plurality of pallets from an edge of the first or second pallet rail to the second or first pallet rail. The pallet moving means move on a semicircular path between two positions that face each of the both end portions of the first and second pallet rails.
In such a circulation-type pallet transport device, the pallets are transported by the first or second pallet feeding means while being placed on the first or second pallet rail, and then moved from the edge of the first or second pallet rail by the pallet moving means on a semicircular path. The pallets are connected to the edge of the second or first pallet rail, moved to the second or first pallet rail by the second or first pallet feeding means, and placed on the second or first pallet rail again. In this way, the plurality of pallets are circulated on a track shaped path.